Method and apparatus for removing vapors



Dee. 10, 1929. I H. w. cowAN 1,738,641

METHOD AND APPARATUS Fon nEMovING vAPoRs Filed April 4, 1927 2Sheets-Sheet 1 10 Q- Jr A l IIIHI;

Dec. 10, 1929. H. w. cowAN I METHOD AND APPARATUS FOR REMOVING VAPORSFiled April 4, 1927 2 Sheets-Sheet 2 INVENTE.

Patented Dec. 10, 1929 PATEISJ'Iv OFFICE-f HENRY w. coWAN, or T oRoNTo,ONTARIO, CANADA METHOD AND APPARATUS FOR REMOVING VAPORS Application ledApril 4, 1927, Serial No.

Thisinvention relates to vapor .removing means adapted particularly foruse with drying apparatus such as used in connection with themanufacture of paper. According to present .methods the paper afterleaving the making screen is led between drying rolls. These dryingrolls are hollow and are heated internally by steam. In some cases,also, the paper may be led over suitable rolls in close proximity toheated coils.

The heat from the drying rolls or coils converts the moisture in thepaper into the form of vapor, and various arrangementsv have beentriedto get rid of this vapor.

None of these arrangements have been entirely satisfactory andconsequently the room in which the apparatus is located is constantlyfilled with vapor which'lis liable to condense and be redeposited andwhile the room is maintained atv a high temperature, which is extremely.uncomfortable for the workmen as well as dangerous to their health,this temperature is not sufficient to maintain the moisture in thevaporized form until the vapor escapes from the room.

i y My object therefore is to devise means for getting rid of this vaporwithout allowing it to pass into the room in which the drying apparatusis 'located and at the same time 3o to enable me to use air formaintaining the moisture in the vaporized form of a much highertemperature than formerly while maintaining the temperature of the roomas a whole at a comfortable degree and to utilize said hot air in such amanner that no cross currents will be created tending to hinder thetravel of the moisture laden air from the drying rolls. A further objectis to provide means for removing the moisture from the air whereby theair may be again circulated, thus avoiding the necessity of always usingthe cold outside air, which naturally is more expensive` to heat up thanthe previously heated air which may not have been fully saturated duringthe previous circulation and which is only partially cooled during theprocess of removing the moisture therefrom.

While the invention is particularly adaptable frr use in the drying ofpaper, it is also 180,903, and in canada october 29, 1926.

of value in removing vapor inconnection with other apparatus, such,for'example, as vapor rising from dye kettles in dye housesI and thisand similar uses all fall within the scope of my invention.

I attain my object by means of the apparatus hereinafter describedandillustrated in the accompanying drawings in which Fig. 1 is a moreor-less diagrammatic view, partly in section, illustrating the apparatusfor carryingout my invention;

Fig. 2 a longitudinal section of the casing for thel drying rolls on theline 2-2 inj Fig. 1; v

Fig. 3 a similar view `on the line 3 3 in Fig. 1; and

Fig. 4 is a view similar to Fig. l showing my invention as used inconnectoin with the removal of vapor rising from dye kettles.

- In the drawings like numerals of reference indicatecorresponding partsin the different figures.

Referring particularly to Figs. 1 to 3, 1 indicates a suitablesupporting frame in which are journalledthe rolls 2 of themachine over.which the-paper is led during the drying operation. In actual practicethese rolls may be steam heated as is common in the vartor heating coilsmay be positioned in close proximity thereto. The frame with its rollsis enclosed in a housing 3 located in aroom, the latterA being indicatedby the Wall 30. This housing is open at one side and is provided with aslot in each end for the passage of the-paper to and from the dryingrolls. At thetop of thehousing at its open side is formed a hot airsupply duct 5.

To one end of this duct is connected one end of a-hot air supply pipe 6,the other end of which is connected withan air heater 14. The duct isprovided with a plurality of outlets 7 in its side throughout its'lengthand for the purpose of equalizing the discharge through each outlet, theduct is preferably tapered from end to end, the end of the sup-' plypipe 6 being connected with the end of the duct having the greatestcapacity. y At the opposite or closed side o the housf ing 3 adjacentthe top thereof is provided a collecting duct 8 having inlet openings 9of the inlet openings 9 is, for a purpose which will hereinafter appear,greater than the total effective area of the outlets 7 of the hot airsupply duct.

To the exhaust duct is connected one end- 0f a suction` pipe 10.

The collecting duct 8 has within it a series of longitudinal gutters 11,one below each row of inlet openings 9, and along these gutters are laidcold water pipes 12 perforated in a suitable manner to direct sprays ofcold water, the water being collected in the gutters and led off througha discharge pipe 13 for re-use.

The suction pipe 10 preferably leads to a mixing chamber 15 to whichmixing` chamber is also connected a pipe 16 through which fresh cool airmay enter. From the mixing chamber leads a pipe 17 which leads to asuction fan 18, which fan discharges a pipe 19, which leads to abranched pipe 14, one branch leading both to the heater and the otherbranch to the atmosphere.

The mixing chamber 15 is preferably provided with baiiles 20 to `causethe air to take a circu'itous course therein and from the mixing chamberleads a waste pipe 21.

If desired I may employ a fan 22 in the branch of the pipe 19 leading tothe atmosphere for the purpose of assisting the exhausting of airthrough said pipe.

In the pipe 19 I preferably provide a damper 23 while in the cold airinlet pipe 16 is also provided a damper 24. These dampers 23 and 24 arepreferably connected by means pf a link 25 so that they will be actuatedsimultaneously and thus the incoming of air through the pipe 16 will beproportional to the exhaust of air through the branch of the p ipe 19which leads to the outside air.

The method of operation is as follows: Heated ,airl from the heater 14is led through the pipe 6 to the duct 5 from which it is dischargedthrough the openings 7 into the upper part of the housing 3. The hot airnaturally tends to remain near the top of the housing and as the inlets9 of the collecting duct 8 are also near the top of the housing, thenatural ow of the hot air is directly across the upper part of thehousing from the duct 5 to the collecting duct 8. To reduce the dau gerof hot air escaping into the room 30 I prefer to arrange the hot airduct and its discharge so that the air is directed across the housingtowards the discharge opening. One of the most important features of myinvention is, however, my arrangement whereby more air is withdrawnthrough the" duct 8 than is discharged through the duct 5. This extra.air must come therefore through the open side of the housing and itcarries upward with it the vaporformed b v the passing of the wet paperover the heated rolls and is mixed in the upper part of the housing withthe hot air from the duct 5. The mixed air and vapor is drawn into thecollecting duct where it is immediately cooled by means of the waterspray from the pipes 12, thus causing the vapor in the air to condense.The air having lost a large percentageof its moisture passes through thepipe 1() to the' mixing chamber 15, where. most of the remainingmoisture is condensed by contact with fresh cold air entering throughthe cold air pipe 16. The condensed moisture gathers in the bottom ofthe mixing chamber, and isled off through the waste pipe 21.

From this it follows that the air upon being returned to the heater haslost much ofy the moisture taken up in passing throughthe housing 3 andis therefore more easily reheated before it again passes to thehousing.v Further, the air even after going through the coolingoperations will not be as cold as the outside air, at least in all butthe hottest summer weather, and consequently the expensev of heating theair willnot be as great as if all fresh air was always used to carry offthev vapor created in the drying operation.

According to weather condltions through the open side ensures that thevapor formed in drying the papei` is directed into the course of the hotair to be carried off` thereby to the collecting duct.

It will thus be seenthatvery llitle vapor may enter the room in whichthe apparatus is located and also that practically no hot' air willescape into saidproom. From this it follows that I may heat the air usedfor maintaining the moisture in the vapour form to a much greaterextentthan formerlywith# out creating an unduly hlgh temperature 1n theroom, thus ensuring a more efficient op eration without endangeringthehealth of the workman.

the amount of air admitted through the cold air pipe 16 or allowed. toescape through the ex-v of the pipe 19 may be varied as lio It will alsobe apparent that the hotiair is discharged into and removed 4from thehousing in such a manner that the carrying off of the moisture ladenairis accomplished with-'pv out the creation of any interfering crosscurrents or eddies. y In Fig. 4 I illustrate a lay-out for use inconnection with dyeing apparatus. 22a in'di` `cates a dye kettle intowhich the material bein;r dyed is dipped. The kettle is enclosed in ahousing 23 having ailar'ge opening 2 4 for the entrance of air from theroom. lTo

leo

the top of the housing is connected a conduit 25a which leads to acondenser 26, which contains a water spraying device for c ondensing thevapors. At the bottom of the condenser is placed an outlet'27 for thewater and condensate, which outlet is led to a tank 28. To the side ofthe condenser is conneeted the suction pipe which leads to the a portionof the air to the atmosphere.

In order that the inflow of fresh air through the pipe 16 and thedischarge of air through the branch pipe 29 may be suitably regulated,

Apipe 16. In Figf4 I show the pipe 10 leading vset out in the preambleof the the former is provided with a damper 24 and the latter with adamper 23.

In the arrangement shown in Fig. l as well I as the arrangement shown inFig. 2, the discharging of a portion of the air from the fan 19 to theatmosphere through the branch 29, is very important, as in this way thedesired result of forcing less air into the housing than is withdrawntherefrom is obtained. The amount of air discharged through the pipe 29must, of course, be greater than'the amount of fresh air admittedthrough the ack to the housing 23, butin the case ofa dyeing plant, forexample, where highly heated air is not essential, the dotted portion ofthe pipe 10 my be omitted so that the pipe discharges into the roomsothat all air enteringr the house enters through the opening 24a.

- In every case, it is very important to ensure a proper disposal of thevapors to return less aip to the housingor room than is dra-wn ofi'v bymeans of Ath`e pump, and, as will be seen from the foregoingdescription, this is accomplished by discharging a portion of the airdrawn off by the pump to 'the atmosphere, thesremainder only beingre-heated and returns tothe roonror housing. n. i

From the above description it will be seen that I have devised a processand apparatus for removing vapors which will satisfactorily attain' theobject of my invention as specification. What I claim is 1. The processof preventing vapors arising from heated liquid or moisture containingmaterial located in a partially open housing from escaping into a roomin which said housing is located, which consists in constantly supplyinghot air to said housingfor moisture-absorbing purposes,` andcontinuously withdrawing air and vapor from the housing at a rategreater than the combined inflow of hot air^and formation of' vaporwhereby aconstant inflow of air is maintained throughthe open portionofthe housing.

2. The process of preventingvapors aris'- ing rfrom heated liquidor-moisture containing material located in a partially op'en housingfrom escaping into a room in which said housing is located, whichconsists in' constantly supplying Ahot air to said housing formoisture-absorbing purposes, constantly withdrawing air' and vapor fromvthe housing at a rate greater than the combined inflow of hot air andformation of vapor whereby a constant inflow. of air is maintainedthrough the open portion of the housing, discharging a portion Iof thewithdrawn air to the atmosphere, and reheating the remainder g of thewithdrawn air and returning it to the housing as at least part? of theheat'ed air aforesaid.

3. The process of removing vapors arising from heated 'material,containing moisture, which consists in arranging said material in ahousing located .in a room in which the operators work, said housinghaving an opening through which atmospheric airmay enter,

constantly supplyinghot air to said housing at an elevation entirelyabove the material, and constantly withdrawing air from the upperportion of said housing at a point remote hot air and at a'ratesufficient to reduce the pressure in the housing, and thus maintain aconstant flow of air through said opening tothe interior of the housing,whereby the escape of vapors froml the housing through said opening isprevented.

' 4. The process of removing vapor arising from heated materialcontaining moisture, which consists in .arranging said material 1n ahousing located in a room in which the operators work, said housinghaving an opening tl-irou'gh which atmospheric air may enter, constantlyintroducing hot air into said hous-v ing' at an elevation entirely abovethe material, constantly withdrawing air from` the upper port-ion'ofsaid housmg at a point' remote from the point of introduction of the hotair and at a rate suflicient to reduce the pressure in the housing, andthus maintain a constant flow of air throughsaid opening into thehousing, allowing a portion of said withdrawn air to escape totheatmosphere, and reheating the remainder of the 'with-- l drawn airand returning it to the housing.

5. The process of removing vapor arising from heated material containingmoisture, which consists in enclosing saidv material in a housinglocated in a room in which the operators Work, said housing having anopening in one ofl its side walls through wiich atmospheric air mayenter the housing", constantly forcing hot air to said housing at anelevation entirely above the material, and

from the p'oint of introduction of the f 4' f Y' l1,738,641

constantly-withdrawing air from the upper part of said housing at apoint remote from the point ofintroduction of the hot air, and

at a rate suicient to reduce the pressure in' the housing and thusmaintain a. constant flow of air through said opening to the interior ofthe housingwhereby -the escape of vapors through said opening isprevented.

6. The process of removing vapor arising from heated material containingmoisture, VV which consists in enclosing said material in a housinglocated in a room in which-the operators Work, said housing having anopening through which atmospheric air may enter, constantly introducinghot air into said housing at an elevation entirely above said mafteria1, constantly withdrawing air from' the upper part of said housing'at a rate suiicient to reduce the pressure therein,and thus to maintaina constant flow of air through said' opening into the housing, allowinga' portion of said withdrawn air to escape to the atmos-- to the meansfor introducing hot air into the housing, means for condensingthemoisture out of the air withdrawn from the housing,

means for constantly discharging a portion of the withdrawn air to theatmosphere, means for introducing aii from the atmosphere into saidconduit, and-means for heating the yair passing through said conduitltothe housing.

Signed at Toronto, Canada, this 19th day of March, 1927. l

HENRY W. COWAN.

pliere, and-'reheating the remainder of the withdrawn air and returningit to the housing. l j

7. The yprocess of removing vapor arising lfrom heated materialcontaining moisture" which, consists in enclosing said material in ahousing located in a room inwhich the operators work, said housinghaving an openz ing through which air'fromth'e exterior of the housingmay enter the latter, constantly supplying hot air to said housing at anelevation. entirely above said material, constant-r ly withdrawingairvfrom the upper portion of said housing at a point remote from thepoint of introduction of the hot air and at a rate sufficient to reducethe pressure in the housing, and thus maintaining a constantl How-of airthrough said opening into the housing, constantly allowing a portion of4said withdrawn air to `escape to the 'atmosphere, and reheating theremainder andre turning it to the'housing..

8. In apparatus for removing vapor aris` ing from heatedmaterialcontaining moisture, the combination of a housing, means therein forheating said material,l said housing having an opening in its lowerportion substantially equal'in length to said heating means, means forconstantly supplyingl hot air to saidhousing at an elevation entirelyabove the heating means, and means for constantly withdrawing air fromthe upper portion of saidhousing at a rate sulicient to reduce thepressure therein, andthus maintain a flow of air through said opening tothe interiorA of the housing, whereby the escape of vapors from thehousing through said opening is prevented'.

9. In apparatus for removing'vapor'arising `from heatedmaterial.containing-moisture, the combination of a. housing,means in thehousingfor heating said material, said housing having an opening itslower uportion Alas

